With a traditional tactical style design, the second generation Sidefire SSAR15 SBS Stock adds rapid fire mode to your AR-15 semi-automatic rifle. Features High Strength Polymer No Permanent Modifications Traditional Battle stock design Enables rapid fire mode Most third party sling attachments are not compatible. See our S.P.A.D.E. Compatibility Fits AR-15 with Carbine Style Buffer Assemblies. Compatible with mil-spec and most commercial buffer tubes.